Highlight < 0.9.3 - Authenticated (Admin+) Stored Cross-Site Scripting
Strategic Overview
- Status
- Patched in 0.9.3
- Affected Plugin
- Highlight Sitewide Notice, Text, Button Menu
- Affected Version
< 0.9.3- CVSS
- 5.5Medium
- Weakness type
- CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- CVE
CVE-2021-24591
At a glance
CVE-2021-24591 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Highlight Sitewide Notice, Text, Button Menu WordPress plugin, affecting versions < 0.9.3. It carries a CVSS score of 5.5 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Admin level or above. The issue is fixed in version 0.9.3; sites on affected versions should update now. Disclosed August 2021, reported by xiahao.
Vulnerability Overview
The Highlight WordPress plugin before 0.9.3 does not sanitise its CustomCSS setting, allowing high privilege users to perform Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no interaction from a victim user.
CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Reaching this weakness in Highlight Sitewide Notice, Text, Button Menu < 0.9.3 takes an account at Admin level or above. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.
Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For Highlight Sitewide Notice, Text, Button Menu the fix is 0.9.3: builds < 0.9.3 are affected, anything from 0.9.3 onward is not.
Remediation
Update to version 0.9.3, or a newer patched version
How does WordSec protect against this?
An attacker needs Admin access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Highlight Sitewide Notice, Text, Button Menu 0.9.3 closes this, and updating the plugin is the step that ends it.
- Firewall
- Alerts
External References
Related records
Other vulnerabilities in Highlight Sitewide Notice, Text, Button Menu
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